Weak mid-gap spin susceptibility anomaly ofLiVGe2O6with nonmagnetic impurities

Abstract

The magnetic susceptibility of mid-gap states of the one-dimensional gapped $S=1$ Heisenberg model is calculated in this paper. These mid-gap states are generated by nonmagnetic impurity bonds introduced by crystal defects, such as dislocations, stack faults, etc. Using the relation between the gap magnitude of the mid-gap state and the strength of the impurity bond, we explain the weak mid-gap spin susceptibility anomaly in the experimental data of ${\mathrm{LiVGe}}_{2}{\mathrm{O}}_{6}.$ We find that the position of the weak anomaly is well explained by assuming that it comes from nonmagnetic defects. Our explanation shows that the weak anomaly will be weaker if there are fewer crystal defects and nonmagnetic impurities.